1. Field of the Invention
The present invention relates to a semiconductor packages, and in particular relates to a photosensitive semiconductor package.
2. Description of the Related Art
In conventional semiconductor packaging, a semiconductor chip is encapsulated with an opaque encapsulant for preventing the chip from being damaged by external contaminants and moisture, as well as protection against damage from external impact. However, in respect to a photosensitive semiconductor chip for use in an electronic device such as a CMOS image sensor, the chip requires a photosensitive side to receive external light. Therefore, a different method for packaging such a photosensitive semiconductor chip is adopted, as compared to the foregoing conventional semiconductor packaging method.
In conventional semiconductor packaging manufacturing methods, there have been several patents regarding the packaging of photosensitive semiconductor chips. A common semiconductor package for accommodating a photosensitive semiconductor chip is illustrated in FIG. 1, comprising: a wafer 100 defined having a photosensitive device 102; an dam 104 formed on the wafer 100 with a cavity for exposing an expose area 110; and a transparent cover 106 attached to a top of the dam 104, wherein the transparent cover 106 is positioned right above the photosensitive chip 102.
Generally, a commercially available transparent cover (e.g. a glass slice) is applied with an epoxy resin adhesive at positions attached to the top of the packing layer. After heating and applying pressure, the adhesive melts and solidifies to firmly attach the lid onto the top of the dam.
However, compression between the transparent cover 106 and the top of dam 104 easily results in leakage or loss of the adhesive 108, because the top of the dam 104 is flat. Additionally, if the adhesive flows over the dam to the expose area 110, the leaked adhesive will lead to contamination of the photosensitive chip and thus, manufacturing yield lost. Thus, to obtain an excellent semiconductor package, a novel packaging method and package structure are required for photosensitive semiconductor devices.